An interesting sighting
 

The refurbished bin of a local hardware had an odd wacker. It was a Craftsmen 25cc propane powered 4-stroke. The actual short block was very trim. The crank is supported on both ends. It is more like a chainsaw than a wacker crankcase. The carb is a .........well who cares. It looks like a 4-stroke carb could be bolted on. It appears to be a splashed lubed type with a drain plug on crankcase. Compared to the briggs 4-strokes I have been nmessing with it is very svelt.

Anyone mess with one yet?

RE: An interesting sighting
 

http://www.golehr.com/products.shtml

RE: An interesting sighting
 

I've kinda wanted to put one of those on a plane stock on propane... they make short bottles with that connector to reduce the weight. A cub or big stick could handle it, you would definetely be the only one with one :)

RE: An interesting sighting
 

I would bet that those little butane cans for back packers' stoves could be made ot work. It is an intersting engine, like a tiny chainsaw engine, very cute. If I can get one for cheap I will abuse it well.

RE: An interesting sighting
 

probably could, but I've seen half size propane canisters in the camping section too, probably weigh about the same, harbor freight has the refill thing for $18 for that style canister...

RE: An interesting sighting
 

One thing you guys aren't thinking about.... If this engine is optimized for use on Propane, and one would assume it is, then it should have a good, high, compression ratio. It should make better power on gas than other four strokes, assuming the porting, valves, and cam are decent. That is one of the limiting factors with, for example the Honda GX-31 engine; a low compression ratio and no reasonably easy way to raise it.

AV8TOR

RE: An interesting sighting
 

HHHhhuuuumm.....very interesting inded!!!!!!!!!!!http://www.rcuniverse.com/forum/js/f.../thumbs_up.gif Capt,nhttp://www.rcuniverse.com/forum/js/f...unge_smile.gif

RE: An interesting sighting
 

You guys are killing me. I might have to go haggle with the manager. He is very open to crazy low offers. If I resist the temptation to cut pieces it could always be restored to wacker service if it does not work out. Hmmm indeed.

RE: An interesting sighting
 

I am somewhat familiar with these Craftsman propane trimmers. They are built by Lehr, a company that has a line of propane powered lawn equipment products. The engine on the trimmer you are considering has a Chinese built version of the Japan built Subaru Robin EH025 with a propane carburetor system.

The Subaru Robin EH025 does have conversion potential, and is the base engine for the The Fuji Imvac BF-25EI

http://www3.towerhobbies.com/cgi-bin...?&I=LXJDJ5&P=7

I do not know if these Lehr engines are any different internally from the EH025 as far as compression, or ignition or valve timing though.

If you decide to pick up the trimmer and chuck the propane system parts, I'd like to buy those parts to use on a motorized bicycle project I am working on.

RE: An interesting sighting
 

I found this deal, $99 at sears. I am not sure of the details.

http://www.craftsman.com/shc/s/p_101...11000&sLevel=0

RE: An interesting sighting
 

Thanks for the link Scota, that's a pretty good price...

I actually purchased two of them this fall at the Hayward CA store for $54 each (new in the box), but someone broke into my van and stole them before I had even opened the boxes.:(

Then I bought a couple used ones off eBay, but one of them had some of the parts of the propane system fiddled with and some parts broken and missing.

These engines look pretty good, but the parts are not as nicely finished as they are on the genuine Subaru EH025 engines. I have no specific reasons to think so, but I doubt that these engines are any different inside than the gasoline engines.

An engine running on propane produces about 2/3 the power as it does on gasoline - provided you have upped the compression ratio and advanced the ignition timing. As these are a four stroke (heavy), and you would also have a heavier fuel tank than with gasoline (plus a regulator), I don't think propane has much promise in an airplane conversion.

RE: An interesting sighting
 

I run propane engines at work for industrial use, we start with standard GM engines and make them dual fuel or propane only. We only run them to 3000rpm and they actually produce more power than gasoline at that speed on some of the engines. The issues with higher speeds are higher exhaust temperatures since you can't just add more fuel like you can on gasoiline to reduce the exhaust temperature, and getting a system that will have the correct air fuel mixture for all speeds. I doubt the EGT would be an issue on these small engines.

RE: An interesting sighting
 

what is the fuel consumption? I have worked with propane V-4s(old Wisconsin cast iron motors) in the past, and they seem to last forever vs. gasoline. We ran them in a nasty, nasty environment, and even with little PM, they seemed to last forever.